1. Field
This disclosure relates generally to semiconductor device packaging, and more specifically, to providing through-package vias in an encapsulated device package by forming signal conduits prior to the encapsulation process.
2. Related Art
Semiconductor and other types of electronic devices are often encapsulated wholly or partly in resin to provide environmental protection and facilitate external connection to the devices. Subsequent to encapsulation, interconnect structures can be built up on one or both sides of the encapsulated devices. For packages having electrical contacts on both top and bottom surfaces (e.g., for package-on-package applications), through-vias are often made to provide contacts between bottom side and top side interconnect structures. Traditionally, through package vias are made after encapsulation using a drilling and filling/metallization process that includes steps for via drill, via fill/metallization, polish and taping, and so on. This process of post-encapsulation via formation introduces complexities to the manufacturing process that have a variety of manufacturing and reliability challenges (e.g., consistent integrity of the through via and reliable connection to the interface). Further, costs associated with materials, processes and additional tooling to generate the through vias can be high.
It is therefore desired to have a process for creation of through package vias before encapsulation. It is further desired that the mechanism for providing through vias allows for formation of the through via using photolithographic processes similar to substrate fabrication technology. For enhanced package-on-package connectivity, it is further desired that the pre-fabricated through vias be incorporated to a printed circuit substrate having interconnect pads. The printed circuit substrate will also permit incorporation of semiconductor devices needing either wire bond connections to a package interconnect or flip chip couplings (e.g., conductive balls) to the package interconnect.
The use of the same reference symbols in different drawings indicates identical items unless otherwise noted. The figures are not necessarily drawn to scale.